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AXPO had two datacenters, approximately 30 miles (50 km) apart. Each data center hosted a Citrix XenApp server farm, which was provisioned dynamically using Citrix Provisioning Services (PVS). AXPO used replication between the sites to keep the vDisks at both sites synchronized and to provide disaster-recovery (DR) capability. For the next phase of the implementation, the company was preparing to rollout Citrix XenDesktop to thousands of users. AXPO had three significant requirements for their VDI environment: high availability, a consistent user experience and a cost-efficient infrastructure:
High Availability (HA) - AXPO needed a high availability environment for its Citrix XenApp and the planned XenDesktop rollout. This required multiple servers for Citrix Provisioning Services (PVS), so that the service could remain available during maintenance windows or in the event of server failure.

Consistent User Experience - AXPO needed to avoid a degraded user experience during peak usage periods, which were most noticeable during start-of-day logons. AXPO had previously required additional Provisioning Servers and storage to support I/O requirements.

Cost-Efficiency - AXPO needed to minimize upfront and on-going storage expense. Each Provisioning Server required access to all of the XenApp and XenDesktop images. Replicating the images among the storage volumes assigned to each Provisioning Server added complexity and overhead, as well as increased storage cost.

After a careful review and evaluation process of available options, AXPO selected Sanbolic's Melio VDI software to provide seamless scale-out of Citrix XenDesktop and XenApp, while delivering consistent performance and improved storage utilization. Active/active storage access and centralized management through the Melio platform also proved critical features to ensure image availability and simplified management. AXPO obtained the following benefits with the Sanbolic Melio VDI solution:
Flexible scale-out to thousands of Citrix desktops, while meeting availability requirements and customer service-level expectations.

Reduced storage capital requirements by more than 50%, by eliminating the need to have redundant local copies for each Provisioning Server.

"Being prepared to scale out to thousands of virtual desktops without additional hardware cost, and knowing that we are optimizing server and storage utilization without slowing down daily operations, is worth a lot to the entire team here at AXPO," said Daniel Fritz, Team Manager, AXPO. "Sanbolic's Melio VDI made this vision a reality."
Fritz continued, "We are now storing all our images on Melio volumes for high availability. Melio VDI lets us add servers and expand volumes on-the-fly without reboot or downtime. We are prepared to scale to 2,000 XenDesktops at any point."
"Sanbolic's Melio VDI delivered the high availability, ease of maintenance and seamless scale-out AXPO required for its Citrix XenApp and XenDesktop environments. By managing files and application data independent of the underlying storage medium, Melio now enables its storage volumes to be easily migrated across hardware and sites to meet varying service levels and availability requirements," said Eva Helen, President, COO and Co-Founder, Sanbolic. "Each AXPO data center can now use a single shared copy of the images, thereby dramatically increasing utilization and simplifying management. Moreover, Melio's embedded replication capability ensures the most recent copies of all vDisks are synchronized between both data centers in the event of a site-wide failure." She continued, "With Melio VDI's scale-out capabilities, AXPO can now add additional PVS servers and storage resources on the fly, without requiring a maintenance window. This allows AXPO to maintain optimal user experience as they continue to support a growing number of third-party customers."
Technical Specifics of AXPO's Sanbolic Melio VDI Solution
AXPO now uses Sanbolic's Melio VDI software to enable multiple PVS servers within each datacenter to share concurrent access to a single volume that contains all the XenApp server image files (vDisks) or XenDesktop images. Melio VDI provides active/active storage access to multiple PVS servers, allowing AXPO to store hundreds of XenApp image files in two volumes: one volume accessed by the PVS servers in the first data center and the second volume accessed by the PVS servers in the second data center. This configuration greatly simplifies vDisk management and maintenance. It also provides continuous vDisk availability in the event of PVS server failures. Melio VDI now also supports the dynamic addition of PVS servers and on-demand volume expansion, while the Citrix environment remains on-line. This enables seamless scale-out of the infrastructure to support thousands of desktops, maintaining a consistent user experience even during morning boot storms.